John b



UNITED STATES.

PATENT OFFICE.

JOHN B. BOLLMAN, OE DAYTON, OHIO, ASSIGNOR OF ONE-HALF TO THEODOR H. HUEWE, OF SAME PLACE.

METHOD OF AND SOLUTION FOR TANNING.

SPECIFICATION formingpart of Letters Patent No. 262,924, dated August 22, 1882.

Application filed February 18, 1882. (N0 specimens.)

To all whom it may concern:

Be it known that I, JOHN B. BOLLMAN, of Dayton, in the county of Montgomery and State of Ohio, have invented certain Improvements in Methods of Tanning, of which the following is a specification.

My invention relates to a method of and solution or compound for tanning; and the essential feature of the invention consists in retaining the blood on the skins or restoring it thereto if removed by any step of the process.

Hitherto it has been the practice in tannin g to first wash or soak the hide or skin in water for the purpose of removing the blood therefrom, then draining ofi the water and blood, and subsequently placing the skins or hides in a vat containing lime and water for the purpose of removing the hair. By the removal of the blood and the treatment in the lime-vat the life of the skins or hides is destroyed in a great degree, and as a consequence it is difficult to produce a tough, pliable leather, or to secure a firm, smooth surface. By my plan, however, the life of the leather is preserved, and as a consequence a tough leather, soft and pliable, yet possessing a firm, smooth surface, is produced. I

In carrying out my invention I prefer to soak the skins or hides in water, as heretofore, as I find that when this is done in connection with other steps of myprocess a finer article is produced than when the washing is omitted, as I propose in some cases. i

The preferred manner of carrying out my plan may therefore be described as follows:

, The hides or skins are first soaked in water to remove the blood and like adhering matter, after which they are removed from the water and drained off. The skins are then placed in a vat containing Water, lime, and blood in about the proportions of one bushel of lime and one and a half gallon of blood to fifteen varied but the formula given is preferred, be-

ing found in practice to give excellent results.

In some cases the first washing may be dispensed with andthe skins placed at once into the lime-vat, in which case, the skins already containing a considerable quantity of blood, the'amount separately added to the water of thelime-vat may be materially lessened. While so far as it goes I consider this plan the equivalent of the first, and as'included within the limits of my invention, I do not deem it the full equivalent of the first-described method, because I find by actual experience that it does not produce as fine a quality of leather. I have also found in practice that hides or skins treated in this way require a much less prolonged soaking in the tan-bark solution than hides treated in the old way, the difl'erence in time being as one and three, and from that to one and ten.

Leather prepared in accordance with my method is soft and pliable, yet tough and firm, and will not become rough with use or wear, and will shed or exclude water far more perfectly than leather prepared by other plans. Again, I am enabled to accomplish the tanning operation with a far less quantity of bark than is required by other plans, from one-half to one-quarter the usual quantity being sufficient.

Under the ordinary plan of treatment the skins have to be taken from the lime-vat, worked or treated in one way and another, and replaced several times; and as very commonly carried out the existing plans require the skins to be immersed and soaked for several days in a mixture or solution containing manure. Un der my plan, however, the skins, when taken from the lime-vat, have the'hair removed, and are rinsed off and placed at once into the barkliquor, from which they can be removed, com- I claim is thus permitting other hides to be immersed therein, I also save a great amount of labor.

formerly required in handling the hides in the lime and bark-liquor vats.

I am aware that a bating mixture has been proposed, in which blood and ammonia were to be used (with or without sawdust and urine) with water; and I am likewise aware that it has been proposed to apply blood at its stage of separation from the serum to skins or hides, and therefore [do not claim broadly the use of blood. My invention diifers from the first of these plans in that, instead of being abating solution, it is a depilating mixture designed to render a hating solution unnecessary, by leaving the hides in a soft, pliable, and desirable condition, ready to be placed in the tan-vat. .It differs from the second plan in that by the use of lime the depilating action is materially hastened, while the presence of the blood prevents the injurious effects which would otherwise be occasioned by the lime.

Having thus-described my invention, what 1.. The herein-described method of treating skins, consisting in introducing them with blood into a vat containing lime and water, substantially'as explained.

2. The herein-described method of treating skins, consisting in subjecting them to the action of water, lime, and blood simultaneously, as explained.

3. The method herein described of treating JOHN B. BOLLMAN.

Witnesses:

WILLIAM W. DODGE, THEODOR H. HUEWE. 

